3GPP (3rd Generation Partnership Project) is a project for discussing studying and specifications of a cellular phone system based on a network developed from W-CDMA (Wideband-Code Division Multiple Access) and GSM (Global System for Mobile Communication).
In 3GPP, it has standardized the W-CDMA system as a third-generation cellular mobile communication system and the services are sequentially started. HSDPA (High-Speed Downlink Packet Access) which communication speed is further improved has also been standardized and the services are started.
In 3GPP, it is currently studying a mobile communication system (hereinafter, LTE-A (Long Term Evolution-Advanced) or Advanced-EUTRA) that utilizes the Evolution of the third generation wireless access technology (referred to as LTE (Long Term Evolution) or EUTRA (Evolved Universal Terrestrial Radio Access)) and a further wider system bandwidth to realize faster data transmission and reception.
The OFDMA method (Orthogonal Frequency Division Multiple Access) is a method using mutually orthogonal subcarriers to perform user-multiplexing and is proposed as the downlink communication method in EUTRA.
Technologies applied to the OFDMA method include an adaptive modulation and coding scheme (AMCS) based on adaptive radio link control (link adaptation) of channel encoding and others.
AMCS is a scheme for switching wireless transmission parameters (also referred to as AMC modes) such as an error-correcting method, an encoding ratio of error correction, and a data modulation multiple-valued number depending on channel qualities of mobile station apparatuses so as to efficiently perform a high-speed packet data transmission.
The channel qualities of the mobile station apparatuses are fed back to a base station apparatus by using CQI (Channel Quality Indicator).
FIG. 20 is a diagram of a channel configuration used in a conventional wireless communication system. The channel configuration is used in a wireless communication system such as EUTRA (see Nonpatent Document 1). A wireless communication system depicted in FIG. 20 includes a base station apparatus 100, mobile station apparatuses 200a, 200b, and 200c. R01 indicates a range where the base station apparatus 100 is able to communicate and the base station apparatus 100 communicates with mobile station apparatuses located within this range R01.
In EUTRA, the downlink for transmitting signals from the base station apparatus 100 to the mobile station apparatuses 200a, 200b, and 200c uses a physical broadcast channel (PBCH), a physical downlink control channel (PDCCH), a physical downlink shared channel (PDSCH), a physical multicast channel (PMCH), a physical control format indicator channel (PCFICH), and a physical hybrid ARQ indicator channel (PHICH).
In EUTRA, the uplink for transmitting signals from the mobile station apparatuses 200a, 200b, and 200c to the base station apparatus 100 uses a physical uplink shared channel (PUSCH), a physical uplink control channel (PUCCH), and a physical random access channel (PRACH).
LTE-A follows the basic system of EUTRA. While a typical system uses a contiguous frequency band, it is proposed for LTE-A to use a plurality of contiguous or non-contiguous frequency bands (hereinafter, carrier components or component carriers) in a composite manner to implement operation as one wider frequency band (wider system band) (frequency band aggregation: spectrum aggregation, carrier aggregation). In other words, one system band comprises of a plurality of component carriers each of which has a bandwidth corresponding to a part of the system band that is an available frequency band. Mobile station apparatuses of LTE and LTE-A can operate in each component carrier. It is also proposed to give different frequency bandwidths to a frequency band used for the downlink communication and a frequency band used for the uplink communication so as to flexibly use a frequency band allocated to a mobile communication system.